IRL, everyone dies...sometimes it's better to sacrifice ones life for a cause. And sometimes one can do more good as a martyr. It was worth exploring these things via Superman, even though the manner of his death was so contrived...particularly as the situation was designed to be very temporary.

But General George S. Patton would agree with you to an extent....

No bastard ever won a war by dying for his country. He won it by making the other poor dumb bastard die for his country.